1. Field of the Invention:
This invention relates to new alkyl hydroxyalkyl orthophosphoric acid esters, mixtures thereof, and to a process for their production. The invention also relates to the use of the esters, particularly salts of the ester mixtures, as emulsifiers in cosmetic emulsions.
2. Description of Related Art:
The production of o-phosphoric acid partial esters by reaction of fatty alcohols with phosphorus pentoxide and the use of these esters and water-soluble salts thereof as surfactants and more especially as cosmetic emulsifiers has been known for some time. It is also known that phosphoric acid can be reacted with longchain .alpha.-epoxides to form phosphoric acid-2-hydroxyalkyl esters, for example in accordance with U.S. Pat. No. 3,487,130.
Although the use of esters such as the above, more especially the water-soluble salts of the partial esters, as emulsifiers for cosmetic and other emulsions has long been known, it has now surprisingly been found that finer and more stable emulsions can be produced with alkyl hydroxyalkyl phosphoric acid esters and their mixtures.